Ink jet printer technology is highly dynamic and ink jet printer printheads or print engines are a key component of ink jet printer devices. The processes used to construct such printheads require precise and accurate techniques and measurements on a minute scale. Some steps in the printhead construction process are necessary but can be damaging to the printhead. Such damage to the printhead affects the quality of the printer output, and, therefore, has an affect on the value of the ink jet printer itself.
One example of a technique that can result in such damage is the removal of an etch mask layer from the planarization and protection layer on a semiconductor chip in a given printhead. Printheads consist of a silicon substrate and a plurality of layers including passivation layers, conductive metal layers, resistive layers, insulative layers, and protective layers on the substrate. Fluid feed holes or vias are formed in the substrate and various layers in order for ink to be transferred through the vias or holes to ejection devices on a substrate surface. Such holes are often formed through the semiconductor chip using deep reactive ion etching (DRIE) or mechanical techniques such as grit blasting. A planarization and protection layer is preferably used to smooth the surface of the semiconductor chip so that it can be more securely attached to the nozzle plate. The planarization layer also functions to protect the components between the planarization and protection layer and the surface of the substrate from corrosion and may provide an adhesive surface for attaching a nozzle plate thereto.
Before holes or vias are formed in the semiconductor chip containing a planarization and protection layer, the planarization and protection layer is desirably masked by an etch mask layer. In order to complete the hole formation process, the etch mask layer must be removed. However, techniques sufficient to remove the etch mask layer also may strip away portions of the planarization and protection layer. This undesirable effect results in less protection for the semiconductor chip. If, on the other hand, less aggressive stripping of the etch mask layer is conducted, portions of the semiconductor chip are left with a white insoluble residue from the etch mask layer which makes the chips unsuitable for use. There is, therefore, a continuing need for a process that will remove substantially all of the etch mask layer without damaging the underlying planarization and protection layer.